Heartbeat: calcium belongs in bones not hearts

Abstract

Calcific aortic stenosis (AS) is characterised at the tissue level by inflammation, lipid deposition and calcification of the valve leaflets. Yet, the potential role of dietary calcium supplements in the development or progression of AS is not clear. In this issue of Heart, Kassis and colleagues report the association between dietary calcium supplementation and cardiovascular (CV) outcomes in a retrospective longitudinal study of 2657 patients age 60 years or older with mildtomoderate AS. In the 39% of patients taking calcium supplements, with or without vitamin D supplementation, there was a higher risk of allcause mortality (absolute rate (AR)=43.0/1000 personyears; HR=1.31, 95% CI (1.07 to 1.62); p=0.009), CV mortality (AR=13.7/1000 personyears; HR=2.0, 95% CI (1.31 to 3.07); p=0.001) and aortic valve replacement (AVR) (AR=88.2/1000 personyears; HR=1.48, 95% CI (1.24 to 1.78); p<0.001), compared with those not on calcium supplementation (figure 1). However, there was no association between calcium supplementation and echocardiographic changes in transaortic pressure gradient or valve area. In the accompanying editorial BerglerKlein points out that, compared with calcium supplements, dietary calcium has little influence on serum calcium availability. Importantly, ‘vitamin D supplementation alone remained neutral with respect to AVR and was not linked to any mortality increase in multivariable analyses, so that the assumed beneficial effects concerning osteoporosis and bone metabolism are maintained in patients with AS.’ Hopefully, future osteoporosis studies will focus both on benefits due to improved bone strength and risks related to adverse cardiovascular outcomes (figure 2). For now, ‘In patients with calcific AS and highrisk CV, the present study strongly adds to the evidence that longterm continuous calcium supplementation should be avoided if not mandatory.’ Another important study in this issue of Heart evaluated whether outcomes with